Dynamo-electric machine.



H. G. REIST. DYNAMO ELECTRIC MACHINE. APPLICATION FILED I'EB.29, 190a.

Patented June 15, 1909.

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UNITED STATES PATENT OFFICE.

HENRY G. REIST, OF SOI-IENEGTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOM- PANY, A CORPORATION OF NEW YORK.

DYNAMO-ELECTRIG MACHINE.

Application filed February 29, 1908.

Specification of Letters Patent.

Patented June 15, 1909.

Serial No. 18,89.

To all whom it may concern:

Be it known that I, HENRY G. Enter, a citizen of the United States,residing at Schenectady, in the county of Schenectady and State of NewYork, have invented certain new and useful Improvements inDynamo-Electric Machines, of which the following is a specification.

My invention relates to dynamo-electric machines and more particularlyto such machines when used for driving the rolls of rolling mills andthe like.

if hen dyna1no-electric machines, or steam or gas engines, are providedfor driving rolls, breakable spindles or shafts are placed between themotors and rolls. These spindles break when the rolls are overloaded toavoid the breakage of the expensive rolls. The breakage of the spindlemay cause a severe end thrust on the shaft of the driving machine incase of an irregular fracture. This is caused by the stoppage of therolls, the continued rotation of the dynamo-electric machine and thetendency of the surfaces of the fracture to clear each other. Heretoforeno means have been provided to take care of this end thrust, except bymaking a heavy pedestal for the end of the shaft near the rolls whichwould receive the thrust, transmit it to the base of the driving machineand move the machine from its foundations. Often the dynamo-electricmachine or engine was damaged.

The object of my invention is to overcome these disadvantages when adynamo-electric machine is employed for driving the rolls or similarmachines and to protect the machine from any material damage due to thedescribed end thrust. To this end, I provide the dynamo-electric machinewith a rotatable member which can move in an axial direction whensubjected to a severe end thrust without injuring any part of thedynamoelectric machine.

When the dynamo-electric machine is used for driving rolls there is atall times an end thrust upon the shaft of the dynamo-electric machine.This normal end thrust however, never exceeds a certain definite amountwhich may be estimated or determined by experiment, and an end thrustbearing is provided which will withstand a thrust of this amount. If thethrust is greater than this, due to the breaking of the spindle or othersimilar cause, the fastening means of the end thrust bearing aredesigned so as to break and allow the rotatable member to move axiallywithout injuring any parts other than these fastening means.

Other features of novelty which characterize my invention are pointedout with particularity in the claims annexed to and forming a part ofthis specification.

For a better understanding of my invention, however, reference may behad to the following description taken in connection with theaccompanying drawing in which I have described one embodiment of myinvention.

In the drawing, Figure 1 is an elevation of a dynamo-electric machine,partly broken away to show some details of construction, the parts beingin their normal or operating position Fig. 2 is a view similar to Fig.1, the armature having moved due to a severe end thrust exerted upon it;Fig. 3 is a section through an end thrust bearing provided for holdingthe armature in its normal position; Fig. 4 is an end view of thebearing of Fig. 3 partly broken away and in section; Fig. 5 is anenlarged view of the current collecting device of my dynamo-electricmachine, and Fig. 6 is a section on the line 66 of Fig. 5.

I have chosen an induction motor having a rotor with collector rings andstarting resistance external thereto, for the illustration of myinvention, but it is evident to those skilled in the art that any formof dynamoelectric machine may be used. The stator 1 of the inductionmotor is fastened to the base 2 by means of bolts 3. The rotor 4 has aspider 5 which is mounted upon a shaft 6. The shaft 6 is journaled inbearings 7 and 8 which are bolted to the base 2. At one end of the shaftis a coupling 9 to which is bolted another coupling 10. The breakablespindle or shaft 11 is connected to the coupling 10 by means of acoupling box 12 which is shown in section. Another coupling box 13connects the driving spindle 11 with the driven shaft 14 of the rolls.The coupling boxes 12 and 13 are loosely mounted in place so that thespindle may be inclined at an angle to the axis of the shaft 6, withoutproducing any strain on the couplings. In order to prevent thesecoupling boxes from moving along the spindle, spreader blocks, made ofwood or other suitable material, are inserted in the grooves 15 and buttagainst the central cylindrical portion 16 of the spindle 11.

One or i thereto by means of the bolt 28.

two bearings (not shown) are provided for the spindle, and are usuallyspring supported in order that they may follow theinclinations of thespindle as it drives the rolls. The construction and the method ofsupport? ing such spindles for rolling mills is well known in the art.

On the bearing 8, lugs 17 are east through which bolts 18 pass forholding the end thrust bearing 19 in place. This end thrust bearingpresses against the end of the shaft to hold the rotor or armature inits normal position in the field. I prefer to have these bearings exertabout two hundred tons pressure when the motor is of large output, thatis, from say two thousand to six thousand horse-power. Referring nowparticularly to Figs. 8 and 4, the bearing plate 20, which is made of abrass alloy, is fastened to the end of the shaft 6 by means of screws 21and has a tongue 22 which fits a corresponding gr'oove extending acrossthe end of the shaft. Against this plate 20 is ressed the thrust bearingball 23. This ball has a passage 24 which leads from the top of the part23 to the surface which is in contact with the plate 20. Indentationsare formed both in this surface and in the plate and these indentationsform a pocket 25 for the lubricating material inserted between therubbing surfaces by means of the passage 24. The bearing ball has asquare shaped portion 26 which enters a square aperture in the bearingbracket 27 kept from turning thereby, and is secured The surface 29 ofthe ball is spherical and fits a similar shaped surface of the bearingbracket 27. By making these surfaces spherical the hearing ball tends toadjust its position in the seat formed in the bracket, and consequentlythe flat surfaces of the ball and that of the plate 20 are always insurface contact. The bearing bracket 27 is diamond shaped as seen inFig. 4 and its wei ht is supported by the brackets 30. The b0 ts 18 passthrough holes in the bearing bracket 27, and the nuts 31 are screwedupon the ends of the bolts holding the bearing bracket in place.

Figs. 5 and 6 show in detail the construction of the current collectingdevice which is arranged to move with the armature in case the armatureis subjected to a heavy end thrust. Collector rings 32 are mounted onthe shaft in any usual or preferred manner. Brushes 33 collect thecurrent from these rings and are supported on the brush holder studs 33which are screwed into the cross connections 34. The cross connectionsare mounted on studs 35 extending froin the stands 36, and are insulatedtherefrom by means of bushings 37 and the washers 38. The bolts 39screwed into the ends of the studs 35 hold the cross connections inplace. The stands 36 are fastened to a base plate 40 by means of bolts41. The base plate 40 is supported on, but is not fastened to, Lbeams 42which I have shown as fastened to the pillow block of the bearing 8.These beams may be supported from the base 2 of the machine or in anyother suitable manner. Guide brackets 43 are fastened to the I- beams bymeans of bolts 44. Lugs 45 are cast upon the baseplate, and plates 46are bolted thereto. The plates 46 fit rather loosely in a groove 47formed in the spider 5. This groove, however, may be formed in aseparate collar mounted on the shaft or may be formed in the shaftitself, and further the collar may be fastened to the shaft on the sideof the collector rings away from the armature. When the groove is formedin the spider as shown in Big. 5, the leads from the collector rings arecarried through holes in the spider (not shown) so as not to interferewith the plates 46.

Under normal conditions of operation the relation of parts of mydynamo-electric machine are as shown in Fig. 1 of the drawing. In casethe rolls or other apparatus which is being driven by thedynamo-electric machine becomes overloaded and the breakable coupling isfractured, the rolls stop but the driving machine continues to turncausing a heavy end thrust on the shaft of the machine as the irregularsurfaces of the fracture tend to clear each other. The parts then assumethe osition shown in Fig. 2, the fractured couping being shown at 48. Ithas been found by experiment that the fracture of a coupling which is ofsufiicient cross-section to transmit from two to six thousand horsepower (normal), will not cause a movement of the rotor of the drivingmachine of more than eiglit inches, and consequently the parts arearranged to allow for this amount of movement. When the end thrust comesupon the bearing 19, the bolts 18 being the weakest part of this endthrust bearing break, permitting the end thrust bearing to fall out ofthe way and allowing the end of the shaft 6 to project beyond the end ofthe bearing 8. These bolts may have their heads sheared off, or thethreads, upon which the nut 31 is screwed, stripped, or its tensilestrength may be made low and then it would break between the lugs 17. Inany case these bolts are calculated to withstand an end thrust of abouttwo hundred tons for machines of this size. As the rotor moves over, thelugs 46, attached to the base plate 40, are guided by the groove 47 andthe whole current collecting device is moved over with the rotor. Sincethe stands 36 are fastened to this base plate, the brushes are always incontact with the collector rings. The base plate 40 is guided by theguide brackets 43, and therefore the parts are always centered. If thecurrent collecting de vice did not move with the rotor, the collectorrings would be damaged, due to the e esusz arcing at the brushes whenthey left the rings.

I have illustrated my iHVGlliiUll in connection with an induction motordriving a roll, but it is evident that it may be applied to anydynamo-electric machine driving a device which is coupled to the machineby means of a spindle or shalt which is liable to be fractured, and Idesire it to be understood that my invention is not limited to theparticular construction shown and described, and I aim in the appendedclaims to cover all modifications which do not depart from the spirit ofmy invention.

lv hat I claim as new and desire to secure by Letters Patent ol theUnited States, is,

1. In combination with a driven device. a dynamo-electric machine havinga rotatable member mounted on a shalt arranged to be moved axially inits bearings, and a breakable spindle between the dynamo-electricmachine and the driven device, whereby when the shalt is subjected to asevere end thrust due to the breaking of the spindle, it will moveaxially in its bearings without injuring the parts ol thedynamo-electric machine.

2. In combination with a driven device, a dynamo-electric machine havinga rotatable member mounted on a shalt arranged to be movable axially inits bearings, a breakable spindle between said shalt and the drivendevice, and means lor preventing said shalt from moving axially undernormal conditions.

3. In combination with a driven device, a dynamo-electric machine havinga rotatable member mounted on a shalt arranged to be moved axially inits bearings, a breakable spindle between said shalt and the drivendevice, and breakable means for holding said shalt in its normalposition until subjected. to a severe end thrust.

4. In combination with a driven device, a dynamo-electric machine havinga rotatable member mounted on a shalt arranged to be moved axially inits bearings, a breakable spindle between said shalt and the drivendevice, and breakable means engaging the end ol said shalt lor holdingsaid shaft in its normal position until subjected to a severe endthrust.

5. In combination with a driven device, a dynamo-electric machine havinga rotatable member mounted on a shalt arranged to move axially in itsbearings, an end thrust bearing engaging the end of said shalt andarranged to hold said shalt in its normal position, and a breakablespindle between said shalt and said device, whereby when the shalt issubjected to a severe end thrust due to the breaking ol the spindle, itwill move axially in its bearings without injuring the parts ol thedynamo-electric machine.

6. In combination with a driven device, a

dynamo-electric machine comprising a rotatable member mounted on a shaltarranged to move axially in its bearings, a breakable spindle betweensaid shalt and said device, and means engaging the end ol the shalt forholding said shalt in its normal position until subjected to a severeend thrust, said means including a bearing ball in lrictional engagementwith the end ol said shalt, a bearing bracket supporting said bearingball and preventing its rotation, and breakable means lor lastening saidbracket in place.

7. In combination with a driven device. a dynamo-electric machinecomprising a rotatable member mounted on a shalt, said shalt beingsupported in bearings and arranged to move axially therein, a breakablespindle between said shalt and said device, and an end thrust bearingincluding a bearing ball in lrictional engagement with the end ol saidshalt, a bearing bracket supporting said bearing ball and preventing itsrotation, said bracket being lastened to one ol the shalt bearings bymeans ol bolts, thereby holding said rotatable member in its iuirmalposition with respect to said stationary member until said shalt issubjected to a severe end thrust which breaks said bolts.

8. In combination with. a driven device, a dynamo-electric machinehaving a rotatable member mounted on a shaft, bearings in which saidshaft is journaled, said shaft being movable in an axial direction insaid bearings, an end thrust bearing engaging the end of said shalt,said end thrust bearing being fastened to one of said shalt bearings bymeans of bolts and arranged to hold said shaft in its normal positionuntil said shalt is subjected to a severe end thrust whereby said boltsare broken, and a breakable spindle between said shaft and said device.

9. In combination with a driven device, a dynamo-electric machinecomprising a rotatable member mounted on a shaft arranged to moveaxially in its bearings, a current collecting device arranged to beaxially movable with said shaft, and a breakable spindle between saidshalt and said driven device, whereby when the shaft is subjected to asevere end thrust due to the breaking of the spindle, it will moveaxially in its bearings without injuring the parts of the dynamoelectricmachine.

10. The combination with a driven device, of a dynamo-electric machinecomprising a rotatable member mounted on a shaft, said shalt beingmovable in an axial direction in its bearings, a current collectingdevice, means cooperating with said current collecting device soarranged that said device is axially movable with said shaft, and abreakable spindle between said shalt and said device, whereby when theshalt is subjected to a severe end thrust due to the breaking of thespindle, it will move axially in its bearings f without injuring theparts of the dynamoelectric machine.

11. The combination with a dynamo-electric machine comprising arotatable member mounted on a shaft, collector rings also mounted on theshaft, a current collecting device collecting current from said rings,of a plate to which said device is fastened having lugs engaging agroove portion on said shaft whereby the current collecting device canmove in an axial direction with the shaft.

12. The combination with a dynamo-electric machine comprising arotatable member mounted on a shaft, collector rings also mounted on theshaft, a current collecting device collecting current from said rings,of a plate to which said device is fastened having lugs engaging agroove concentric with the shaft, and guide brackets engaging said plateso that the device can move in an axial direction with the shaft.

13. In combination with a driven device, a dynamo-electric machinehaving a rotatable member mounted on a shaft arranged to be movedaxially in its bearings, a current collecting device, means cooperatingwith said current collecting device so arranged that said device ismovable in an axial direction with said shaft, means for holding saidshaft in its normal position, and a breakable spindle between said shaftand said device, whereby when the shaft is subjected to a severe endthrust due to the breaking of the spindle, it will move axially in itsbearings without injuring the parts of the dynamoelectric machine.

14. In combination with a driven device, a dynamo-electric machinecomprising a rotatable member mounted on a shaft arranged to be movedaxially in its bearings, a breakable spindle between said shaft and thedriven device, a current collecting device, means cooperating with saidcurrent collecting device so arranged that said device is movable in anaxial direction with said shaft, and breakable means for holding saidshaft in its normal position until subjected to a severe end thrust.

15. In combination with a driven device, a L

dynamo-electric machine comprising a rotatable member mounted on a shaftarranged to move axially in its bearings, collector rings mounted uponsaid shaft, a current collecting device having brushes in engagementwith said rings, means cooperating with said current collecting deviceso arranged that said device is movable with said shaft, an end thrustbearing engaging the end of said shaft and arranged to hold said shaftin its normal position, and a breakable spindle between said shaft andsaid driven device, whereby when the shaft is subjected to a severe endthrust due to the breaking of the spindle, it will move axially in itsbearings without injuring the parts of the dynamo electric machine.

In witness whereof, I have hereunto set my hand this 27th day ofFebruary, 1908.

HENRY G. REIST.

Witnesses BENJAMIN B. HULL, HELEN Onronn.

